1. Field of the Invention
This invention relates to an improved mechanism that, installed in a door, operates by pushing or pulling on the door knob in the direction one is opening or closing the door. This invention also fits in the same space as current door latching mechanisms. The simpler motion combined with the reduced effort to operate and the economy of space, makes this a needed product, especially for the mobility impaired.
2. Description of the Prior Art
A patent search was conducted in Class 292, subclasses 166, 168 and 347, and Class 16, subclass 121. These U.S. Pat. Nos. were discovered:
71,474; Nov. 26, 1867; Evans PA1 100,174; Mar. 13, 1870; Bentley et al PA1 236,895; Jan. 25, 1881; Kirwan PA1 480,075; Aug. 2, 1892; Duncan PA1 2,504,483; Apr. 18, 1950; Abraham PA1 2,532,399; Dec. 5, 1950; Fernandez PA1 2,636,763; Apr. 28, 1953; Chapeta et al PA1 3,249,379; May. 3, 1966; Ross PA1 3,264,025; Aug. 2, 1966; Hawes PA1 4,181,335; Jan. 1, 1980; Thoren
This seems to be a crowded field. Of the above, the three most relevant seem to be U.S. Pat. Nos. 236,895 Kirwan, 480,075 Duncan, and U.S. Pat. No. 3,264,025 Hawes. Kirwan's mechanism seems different, and appears to require more effort to actuate. Duncan's mechanism seems different, and also appears to require more effort to actuate. Hawes seems different, more complicated, and bulkier. The effort required by Hawes is reduced by using levers to gain mechanical advantage.
This invention simplifies the process of opening and closing a door. The current invention fits within the space occupied by a convention door latching mechanism that utilizes a rotating motion plus a push or pulling motion. This is important for retrofit installations. This invention reduces the effort, and sometimes pain, by people suffering from wrist pain, arthritis, bursitis, missing fingers, hands or limbs, or other mobility restrictions, when they are opening doors. This invention also makes it easier for small children to exit the room in an emergency situation, such as fire.
The experience of this inventor is that convetional, commercially available door mechanisms, in typical residences, are an obstacle in that the turning motion to operate the door knob is painful and unnecessary. There are no convenient retrofit packages available that simplify the required motion to a push/pull motion. So the present invention was developed, to overcome the aforesaid obstacle. The present invention works with a low push/pull force in the direction of the intended door motion and fits within the confines of existing doors, no door modifications required for installation. The present invention utilizes radii and bushings to lower internal friction which lowers effort. The mechanism designs uncovered in the patent search do not seem concerned with reducing internal friction to lower effort. An indication that the Hawes invention has high internal friction is that levers are required to operate the mechanism.